BRECKENRIDGE — If there is one statistic that best describes Breckenridge Ski Resort’s new Peak 6, it is this: The new terrain, which sits mostly above treeline, increased the size of the ski area by about a quarter, but it increased the ski area’s explosives budget for controlling avalanches by double.

“This is big-game skiing,” said Breck Ski patroller Hunter Mortensen on a recent tour of the expansion. “The lift serves blue runs above treeline that are just phenomenal skiing, but there are also places with a 48-degree pitch and big rock walls on both sides where you can just scare yourself silly.”

Mortensen skied off the new Kensho SuperChair at 12,302 feet and looked out at ski runs pouring off on both sides. Peak 6, which opened Dec. 25, includes 543 acres of new ski terrain to the north of Peak 7, but the big news for many is the 143 acres of advanced, hike-to terrain along the crest of the Tenmile Range.

Breckenridge asked its Facebook friends to name the runs here based on the theme of “awakening the sixth sense.” From the lift, powder seekers can hike a fifth of a mile and 300 vertical feet to a ridge where 20 runs – all rated double black diamond or extreme – fan out on either side.

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Some of the terrain has long been a local powder stash treasured by backcountry skiers because it always had snow and was just the right pitch to allow great powder skiing without too much avalanche risk. Because of this, some backcountry skiers unsuccessfully fought the Peak 6 expansion, saying it would turn a rarely visited playground into a heavily traveled piece of the resort. Others raised concerns that the expansion could impact wildlife.

Breckenridge took extra steps to minimize environmental impact. No roads cut the forests of Peak 6. The lifts and patrol shack were flown in by helicopter. Much of the other work was done on foot.

While the expansion has brought crowds to once solitary basins, it also has opened steep chutes that were often too fraught with avalanche danger for most backcountry skiers to attempt.

Breckenridge installed two air-powered cannons, called Avalaunchers, to lob explosives into the steepest areas from below and added two avalanche technicians to keep the chutes safe.

The result is more of what thousands of skiers and riders who flock to Breck every year love: big, long runs and breathtaking views above treeline.

The most alluring aspect of the new terrain is the range of options.

From the top of the lift, skiers can cut down a pair of long blue runs that are terrain traps for fresh powder. They can opt for a groomed black that plunges nearly 1,000 feet. Or they can hike to a quiver of steeps – some open and smooth, some rocky and tight, some so steep that Breck ski patrol has bolted steel rings into the cliffs for high-angle rescue.

“This is one of the most notable ski-area enhancements in the past decade,” said Rob Katz, chairman and CEO of Vail Resorts. “The new expanded terrain will feature high-alpine, intermediate bowl skiing – a rare find.”

Breckenridge has not expanded terrain since 2002, when Peak 7 opened. Arapahoe Basin added 400-acre Montezuma Bowl in 2007 and Telluride added 400-acre Revelation Bowl in 2008. But Peak 6 is the largest expansion in the state in a decade, and it might be the start of a small rush of expansions. Monarch, Eldora, Wolf Creek and Crested Butte all have proposed expansions in the works.

A tour of Peak 6 showed why it has been a go-to spot for skiers even before it was inbounds. It was a brutal day with a wind that scoured all the powder off the ridges. Down below, fresh snow that had fallen the day before had long since been packed down, but on a Peak 6 run called Bliss, skiers could find soft, fluffy snow into the afternoon.

“The wind will come in and dump fresh snow here all day,” Mortensen said. “We call it free refills.”

EXPANDING ONE PEAK AT A TIMEPeak 8, 1961: Breckenridge is located in the Tenmile Range, which has 10 summits named Peak 1 through Peak 10. Breck originally was called the Peak 8 Ski Area because it was built at the base of Peak 8.

Peak 9, 1971: Originally called Royal Tiger Mountain, this terrain was served by two double chairs.

Peak 10, 1985: Resort added 165 acres of advanced intermediate and expert terrain.

Peak 7, 2002: Resort added 165 acres of intermediate terrain, including seven new trails and the famous Peak 7 glades.

Peak 6, 2013: Resort added 543 acres, including 143 acres of hike-to expert terrain, representing a 23 percent increase in the resort’s skiable acreage. The Breckenridge Ski Area now has 187 trails and 2,908 acres of skiable terrain.

Skiers and snowboarders ride under the new Kensho Super Chair on Peak 6 Monday, Jan. 6, 2014, at Breckenridge. The Peak 6 area opened this year expanding the Summit County resort to 2,908 acres. (The Gazette, Christian Murdock)

CHRISTIAN MURDOCK